Push-button switch assembly



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RUSH+BUTTON SWITCH'E ASSEMBLY 3 Sheets-Sheet 1 F'iTedlMazmh 19, 1962 H wMH III J 7 6 .f 4 E 7 4 4T 4 H9 v VIII- a 6 9 6 4 I HI IHL oWA A 4/ATTY'S.

Dec. 29, 11964 P. re. :RQSS

RUSH-summon swmrrca ASSEMBLY :Sheets-ISheei :5

Filed March 19,, 1962 INVENTOR.

PHILIP C. ROSS ATTY'S.

United States Patent 3,163,740 PUSH-BUTTON SWETCH ASSEMBLY Philip C.Ross, Costa Mesa, Calih, assignor to Patent License Corporation,Chicago, BL, a corporation of Illinois Filed Mar. 19, 1962, Ser. No.189,499 9 (Ziaims. (Cl. 2tt0l63) The present invention relates to a newand improved switch assembly of the push-button type, the assemblymaking use of a unique arrangement of relatively movable parts toprovide efiicient operation and improved compactness of design. Morespecifically, the invention deals with a new and improved push-buttonswitch assem bly particularly adapted for use in the control ofelectronic apparatus such as computers, program controllers and thelike, the assembly including a new and improved switch blade mountingand actuation arrangement and, among other features, a positive gas andmoisture sealing arrangement, all of the improvements being especiallydesigned and arranged for compactness.

With the present day complexities in electronic equipment, such ascomputers, controllers and the like, increasing demands are being madeon the overall operational and design features of component electricaland electromechanical parts. The operating panel of a computer must bewithin prescribed size limitations and yet include the necessary basicswitches or other components required to operate the uni-t. Stillfurther, new uses of computers and the like are continuously being madeand operation thereof can occur under unusual conditions. For example,it may be essential that the computer be sealed from the atmospherewhich might include moisture, damaging gases or the like, or that thecomputer or other control device form a part of a sealed system and mustbe sealed itself.

Difiiculties have been encountered in attempting to reduce the overallsize of basic electromechanical parts, such as switches or the like, andyet retain the requisite positive and dependable operation thereof. Inthis regard the number of moving parts should be maintained at a minimumand the length of travel of such parts should be held as short aspossible. A reduction in the number of moving parts and the length ofavailable travel can adversely affect the basic electro-mechanicalaction required. In this respect, the present invention deals with themaintaining of an adequate distance of travel of a movable contact endof a switch blade between fixed circuit contacts to avoid undesirablearcing and retain adequate positive action, and yet also reduce theoverall size of the switch assembly. Additionally, the invention dealswith limiting the number of moving parts to those which are best capableof resisting damage as a result of extended operation. With improvedcompactness of design constituting the basic purpose of the invention,it is also within the scope thereof to add an efficient sealingarrangement which, by reason of its design, does not interfere with thebasic-purpose in mind.

Therefore, it is an object of the invention to provide a new andimproved switch assembly of compact design and efficient operation.

Another object is to provide a push-button type switch assemblyutilizing a uniquely designed and arranged switching action whichretains the basic benefits of efficient switch operation whilematerially reducing the amount of space required for such operation.

A further object is to provide a new and improved switch assemblyincluding as a part thereof a special sealing arrangement establishingan etficient gas and moisture seal and subject to ready maintenanceWithin minimum space requirements.

An overall object is to provide a new and improved "ice switch assemblycombining therein new and improved electrical and mechanical operatingparts which are arranged to obtain improved efiiciencies both withrespect to continued positive operation thereof and prolong trouble-freelife. 7

Other objects not specifically set forth will become apparent from thefollowing detailed description of the invention made in conjunction withthe accompanying drawings wherein:

FIG. 1 is a fragmentary perspective of the switch assembly of thepresent invention. illustrating the same coupled with a solenoid holdingunit;

FIG. 2 is a fragmentary longitudinal section of the assembly as viewedgenerally along line 22 in FIG. 3;

FIG. 3 is a fragmentary longitudinal section of the assembly takengenerally at right angles to FIG. 2 as viewed along line 3-3 therein;

FIG. 4 is a transverse section of the assembly taken generally alongline 4-4 in FIG. 2;

FIG. 5 is a bottom end elevation of the assembly;

FIGS. 6 and 7 are schematic illustrations. of the operational featuresof the switch blades forming a part of the assembly; 7

FIG. 8 is a perspective of the preferred type of sealing ring used inthe assembly; and

FIG. 9 is a perspective of another form of sealing ring suitable for usein the assembly.

As best shown in FIGS. 1-3, the switch assembly 10 comprises a hollowbody portion 11 of generally rectangular shape provided with atransverse end wall portion 12 closing ofi one end thereof. The oppositeend 13 of the body portion 11 has slidably received therein a.push-button member 14 which is connected through a pair of resilientfinger-like members 15 to a transverse plate 16 mounted in the bodyportion ii and dimensioned for sliding movement therein longitudinallythereof. The transverse plate 16 has attached thereto one end of a pushrod 17 which is suitably journaled through the end wall 12 of the bodyportion and which externally of the body portion may be suitablyattached to a holding solenoid 18 (FIG. 1).

The end wall 12 has mounted therethrough a plurality of fixed contactplates 19. A plurality of reversely arcuately folded switch blades 21Bare mounted in the body portion between the transverse plate 16 and theend wall 12 for actuation in a manner to be described upon longitudinalmovement of the transverse plate 16 in the body portion. A separate butuniquely arranged lamp unit 21 is mounted in the body portion 11 betweenthe transverse plate 16 and the outer end portion of the push-buttonmember 14. The basic assembly is completed by the provision of a specialtype of sealing ring 22 (FIG. 1) or 23 (FIGS. 2 and 3).

Referring specifically to the individual components, the push-buttonmember consists of a continuous transverse end wall portion 24 providedwith an axial peripheral skirt portion 25 (FIG. 3) thus providing themember with a general cup-shape. The resilient finger-like members 15are suitably permanently attached to the outer end surface portion ofthe skirt 25 and project therefrom in oppositely positioned relation inclose association with the internal surface portions or" the bodyportion 11. As best shown in FIGS. 1 and 3, the finger-like members 15cooperate with the transverse end wall 24 and the skirt 25 to definetherebetween a continuous peripheral, outwardly opening groove 26 inwhich the,

.134 which engage the. enlargements 33.

portion and is angled outwardly of the groove 26 for sliding engagementwith inner surface portions of the body portion 11. The chevron sealingring 22 will normally be mounted in the position shown in FIG. 1 inwhich position the interior of the switch assembly is sealed from theatmosphere. Any external gas pressure is active between the flexible lipportion 28 and the base portion 27 to urge the lip portion into tightersealing engagement with the inner surfaces of the body portion 11. 1fthe arrangement is such that the sealing ring is intended to prevent gasleakage from the interior of the switch assembly or the interior of thecomputer or the like, the sealing ring 22 is formed to seal in theopposite direction.

' The sealing ring 23 is of generally solid configuration being providedalong the outer and inner surfaces thereof with peripherally continuousrecesses 29 which define a pair of enlargements to each side thereof fordouble engagement with the base of the groove 26 and the inner surfaceportions of the body portion 11. The operative mounting of the sealingring 23 is shown in FIGS. 2 and 3. This ring is capable of sealing ineither direction at all times.

The unique feature of the sealing rings 22 and 23 is the rectangularshape thereof, this being a predetermined, permanently molded shape. Therectangular or generally square shape of the switch assembly permitsbetter utilization of available space in conjunction with the specifictypes of components making up the same. In attempting to internally sealan assembly of this shape, it has been found that the use of a standardO-ring of the like creates some undesirable problems. Such an O-ring iseither rather tightly received in the mounting groove 26 by reason ofstretch requirements to transform the same into generally rectangularshape, or if over-dimensioned for this purpose, it is too looselyreceived in the mounting groove to permit efiicient functioning.Furthermore, an annular shape which does not conform to the generallyrectangular shape of the switch assembly does not permit theestablishment of an efiicient seal at the corners of 'exact shape of themounting groove 26. In this manner eachsealing ring is mounted in a.substantially relaxed condition in the mounting groove and thefrictional forces exerted against the inner surfaces of the body portiondo not create excessive resistance to the operation of the switchassembly and yet provide a highly efiicient sealing function. Thus byspecial shaping of the sealing rings the same are mounted in relativelyrelaxed confirmation to the rectangular shape of the groove 26 'and bodyportion 11.

The transverse plate 16 is provided with substantial clearance relativeto the inner surfaces of the body portion 11. The plate extends betweenthe inner ends of a the finger-like members with these members beingdetachably connected to opposite margins of the plate 16.

FIG. 3 illustrates opposite margins of the plate 16 being formed withprotecting abutment ledges 31 against which the ends of the finger-likemembers are received for the purpose of applying switch actuatingpressure to the plate to move the same toward the end wall 12 of thebody portion 11. Inwardly ofthe ledges 31 are grooves 32 into whichinwardly directed enlargements 33 formed on the ends of the finger-likemembers 15 are frictionally received. The grooves 32 terminate inlocking tongues With this arrangement the finger-like members 15positively engage the'transverse plate 16 to depress the samein the bodyportion 11 and yet are readily detachable therefrom if the push-buttonmember 14 is grasped and withdrawn from the body portion 11.

The push rod 17 is suitably journaled and fixed in the center of thetransverse plate 16 by an enlarged locking end portion 35. The push rodextends through a sleeve 36 received in a projecting collar 37 formedcentrally in the end wall 12 to define a push rod bore. The sleeveincludes a peripheral enlargement 38 at the inner end thereof which issuitably received in an annular seat formed in the end wall 12 and acoil spring 39 is seated between the inner end of the sleeve 36 and thebottom surface of the transverse plate 16. The sleeve 36 projectsoutwardly beyond the collar 37 and, as shown in FIGS. 1 and 2, isexternally threaded to receive thereon the solenoid 18. A locking nut 40is received on the outer threaded end of the sleeve 36 to hold the samein fixed position within the collar 37. The push rod reciprocatesthrough the sleeve 36 and is formed at its outermost end with anenlargement 41 which overextends the outer end surface of the sleeve 36acting to hold the spring 39 in compression. The enlargement 41 iselectrically responsive to the solenoid holding unit 18 in the knownmanner and upon actuation of the switch assembly 10, the push rod may beheld outwardly in its extended position by the solenoid 18. The switchassembly is not limited to use with a solenoid but this is one of itsstandard uses in accordance with conventional practices involvingcomputer switches and the like. it will be understood that any knowntype of switching action may be accomplished with the switch assembly ofthe present invention, such action including alternate action, solenoidheld action, etc.

The contact plates 19 in the form illustrated are flat metallic stripswhich are fixed in the end wall 12 of the body portion 11 and projecttherethrough externally and internally of the body portion. The outerends of the contact plates lit may be formed with suitable apertures 42for lead connection therewith. Switching action to make and breakvarious circuits controlled by the switch assembly It) is brought aboutby depression of the pushbutton member 14 into the body portion 11accompanied by movement of the transverse plate 16 towards the closedend 12. as previously described. Movement of this plate results inactuation of a plurality of switch blades 20 mounted in the body portionin association with the contact plates 19. The particular switchassembly illustrated involves the use of four switch blades 2% locatedadjacent the four corners of the body portion. The single switch bladeshown in FIG. 1 and the pair of switch blades shown in FIG. 2 areconsidered adequate for the purpose of describing their design andfunction.

It is known that the distance of travel of a switch blade betweencontact points is of material importance with regard to the problem ofarcing as well as fast action. These considerations are not necessarilycompatible as it can be said as a general premise that while a shorterdistance of travel will normally provide faster action, the problem ofarcing becomes greater. Similarly, an increase in the travel reducesarcing and also reduces speed of response. Where adequate space isavailable, these problems canbe readily overcome. However, in attemptingto minimize the space requirements, these problems become rather acute.

The switch blades 2i? and their mode of operation alleviate the problemsof arcing and response while minimizing the space requirements. Eachswitch blade, as best shown in FIGS. 2, 6, and 7, is in the form of areversely arcuately folded resilient member having one end fixed and theother end resiliently movable betweenspaced contacts. Specifically, eachswitch blade 20 includes a relatively flat leg portion 43, the end ofwhich is suitably fixed to the end of a contact plate 19 projecting intothe body portion 11. The leg portion 43 is integrally formed with aresiliently movable leg portion 44 through an arcuate folded portion 45.The leg portion 44 is preferably resiliently bowed in its position ofrest as illustrated and furthermore is preferably inclined at least tosome degree away from the fixed leg portion 43. The free end of the legportion 44 is provided with a multiple face contact 46 which is locatedbetween a pair of contact plates 19 within the body portion 11. In itsmounted condition the switch blade 20 has the contact end thereofconfined between 21 pair of contact plates 19 and the configuration andpositioning of the leg portion 44 is such that the contact 46 iscontinuously held in engagement with one of the contact plates 19. Thebowed and outwardly inclined positioning of the leg portion 44 suppliesa cam actuated surface engaged by an edge portion of the transverseplate 16. Movement of the transverse plate 16 toward the closed end 12of the body portion in the manner previously described results in theriding of the edge portion of the plate along the inclined bowed legportion 44 and ultimate camming of the leg portion and free end contactas thereof away from the initially contacted plate 19 and ultimatelyinto circuit making or breaking contact with the spaced contact plate 19as shown in FIG. 7.

In effect, the switch blade 20 of the present invention is a doubled orreversely folded cantilever leaf spring. By reason of its configuration,the space which it consumes is materially reduced and the distance oftravel of the actuating means, in this case the transverse plate 16, ismaterially shortened. Yet, with this arrangement the requisite distanceof travel to prevent arcing is maintained. Additionally, the life andefficiency of the switch blade is equivalent to a conventionalcantilever leaf blade as the total length of the blade is retained andthe material thereofis not subject to excessive stress or concentratedload. It will be appreciated that the arcuate connecting portion 45 isnot fixed in any respect and only the outermost end portion of the legportion 43 is fixed. This per- .mits full utilization of the resilientand strength properties of the entire blade to accommodate operationalstresses and load. The coil spring 39 functions to return the transverseplate 16 to its initial position as well as return the push-buttonmember to its initial outwardly projecting position. At all times duringtravel of the transverse plate 16 the same is in contact with the switchblades 2!? thus providing for immediate response and control of switchactuation.

The lamp unit 21 is a separate unit mounted in the body portion 11between the transverse plate 16 and the push-button member 14 and iscompletely free from any effect from operational use of the transverseplate and the push-button member. It has been conventional to mount lampunits in the push-button member itself thus utilizing available space.This position of mounting has been found undesirable because of theattendant maintenance of the lamp unit arising from damaging thereof byoperational shock.

The lamp unit 21 is fixedly mounted in the body portion 11 by reason ofa base plate 47 which extends transversely across the interior of thebody portion 11 and is anchored along a pair of opposite margins to thebody portion 11 as shown in FIG. 2. The remaining opposite margins arespaced substantially inwardly from the adjacent surfaces of the bodyportion 11 as shown in FIG. 3. In this space the resilient finger-likemembers 15 extend and are freely movable completely independently of thelamp unit 21. FIG. 4 readily illustrates the clearances establishedbetween the fixed and moving parts. There is sufiicient clearanceavailable to permit ready disconnection of the push-button member 14from the transverse plate 11 for access to the lamp unit for lampreplacement or the like.

The base plate 47 has mounted thereon a pair of lamp mounting clamps 48which resiliently clamp therein lamps 49 having as a part thereofprojecting ears 50 directed upwardly therefrom for ready grasping forlamp removal purposes. As the specific elements carried by the baseplate 47 and comprising the lamp unit 21 are of known type and do notform a part of the invention, they will not be described in detail.Color filters 51 may be mounted about the lamps 49 if desired.

The base 52 of each lamp is in contact with an end portion of a contactplate 1% which extends through the end wall 12 closely adjacent theinner surface of the body portion 11 and is completely free fromengagement or contact with any of the moving parts of the assembly. Theinnermost end of the contact 319 may be resiliently urged intoengagement with the lamp base by a leaf spring member 53 forming a partthereof. The lamp mounting clamps 48 may be suitably attached to acontact plate 19 which also extends outwardly through the closed end 12of body portion. Removal of the pushbutton member 1a provides access forready lamp replacement when necessary.

Obviously certain modifications and variations of the invention ashereinbefore set forth may be made without departing from the spirit andscope thereof, and therefore only such limitations should be imposed asare indicated in the appended claims.

I claim:

1. A switch assembly of the push-button type comprising a hollow bodyportion having an open end and a closed end, a transverse plate in saidbody portion dimensioned for sliding movement longitudinally thereof,push rod means journaled through the closed end of said body portion forreciprocal movement therethrough and fixed to said plate, push-buttonmeans slidably received in the open end of said body portion, saidpush-button means being generally cup-shaped with a continuoustransverse end wall portion joined with an axial peripheral skirtportion and provided with resilient finger-like members projectingaxially therefrom along inner surface portions of said body portion intoreleasable connection with edge portions of said plate, the end wallportion of said pushbutton means projecting from the open end of saidbody portion, said skirt portion inwardly of said end wall portion beingcircumferentially recessed to define a groove opposed to the innersurface portions of said body portion inwardly of said open end, acontinuous sealing ring mounted in said groove and in resilient slidingsealing engagement with said inner surface portions, a plurality ofelectrical contact plates projecting through said closed end on eitherside thereof internally and externally of said body portion, and atleast one reversely arcuately folded switch blade in said housing formedfrom resilient material and having one end thereof fixed to define acircuit connection and the other end thereof provided with a multipleface contact thereon and freely movable between spaced inner ends of apair of contact plates for alternate electrical connection therewith,said switch blade being positioned for camming engagement of the freeend thereof by said transverse plate during movement thereof toward saidclosed end to move said face contact out of engagement with one contactplate and into engagement with another.

2. The switch assembly of claim 1 wherein a lamp unit is fixedly mountedin said body portionbetween said transverse plate and said push-buttonmeans, the fingerlike members of said push-button means sliding freelythrough said lamp unit during movement of said transverse plate.

3. A switch assembly of the push-button type comprising a hollow bodyportion having an open end and a closed end, a transverse plate in saidbody portion dimensioned for sliding movement longitudinally thereof,push rod means journaled through the closed end of said body portion forreciprocal movement therethrough and fixed to said plate, push-buttonmeans slidably received in the open end of said body portion, saidpush-button means being provided with resilient finger-like membersprojecting axially therefrom along inner surface portions of said bodyportion into releasable connection with said plate, a plurality ofelectrical contact plates projecting through said closed end on eitherside thereof internally and ex- .ternally of said body portion, and atleast one reversely arcuately folded switch blade in said housing formedfrom resilient material and having one end thereof fixed to define acircuit connection and the other end thereof provided with a multipleface contact thereon and freely movable between spaced inner ends of apair of contact plates for alternate electrical connection therewith,said switch blade being positioned for camming engagement of the freeend thereof by said transverse plate during move ment thereof towardsaid closed end to move said face contact out of engagement with onecontact plate and into engagement with another, said movable free end ofsaid switch blade forming a part of an inclined leg portion along whichsaid transverse plate slides during switch actuation.

4. The switch assembly of claim 3 wherein a lamp unit is fixedly mountedin said body portion between said transverse plate and push-buttonmeans, the finger-like members of said push-button means sliding freelythrough said lamp unit during movement of said transverse plate.

5 A switch assembly of the push-button type comprising a hollow bodyportion of internal generally rectangular shape having an open end and aclosed end, a transverse plate in said body portion dimensioned forsliding movement longitudinally thereof, push rod means journaledthrough the closed end of said body portion for reciprocal movementtherethrough and fixed to said plate, push-button means of generallyrectangular outline slidably received in the open end of said bodyportion, said push-button means being generally cup-shaped with acontinuous transverse end wall portion joined with an axial peripheralskirt portion and connected with said plate, said skirt portion inwardlyof said end wall'portion being circumferentially recessed to define agroove pposed to the inner surface portions of said body portioninwardly of said open end, a continuous sealing ring mounted in saidgroove and in resilient sliding sealing engagement with said innersurface portions, said sealing ring being of molded generallyrectangular shape for relatively relaxed confirmation to the rectangularshape of said groove, a plurality of electrical contact platesprojecting through said closed end on either side thereof internally andextemally of said body portion, and at least one resilient switch bladein said housing having one end thereof fixed to define a circuitconnection and the other end thereof provided with a multiple facecontact thereon and freely movable between spaced inner ends of a pairof contact plates for alternate electrical connection therewith, saidswitch blade being positioned for camming engagement of the free endthereof by said transverse plate during movement thereof toward saidclosed end to move said face contact out of engagement with one contactplate and into engagement with another.

6. The switch assembly of claim wherein said sealing ring is ofgenerally chevron-like configuration in cross section with a baseportion substantially filling said groove and a flexible lip portionangled from said groove into sealing engagement With said inner surfaceportions.

7. A switch assembly of the push-button type comprising'a hollow bodyportion of internal, generally rectangular shape having an open end anda closed end, a transverse plate in said body portion dimensioned forsliding movement longitudinally thereof, push rod mean-s journaledthrough the closed end of said body portion for reciprocal movementtherethrough and fixed to said plate, push-button means of generallyrectangular outline slidably received in the open end of said bodyportion, said push-button means being generally cup-shaped with acontinuous transverse end Wall portion joined with an axial peripheralskirt portion and provided with resilient finger-like members projectingaxially therefrom along inner surface portions of said body portion intoreleasable connection with edge portions of said plate, the end wallportion of said push-button means projecting from the open end of saidbody portion, said skirt portion inwardly of said end wall portion beingcircumferentially recessed to define a groove opposed to the innersurface portions of said body portion inwardly of said open end, acontinuous sealing ring mounted in said groove and in resilient slidingsealing engagement with said inner surface portions, said sealing ringbeing of molded, generally rectangular shape for relatively relaxedconfirmation to the rectangular shape of said groove, a plurality ofelectrical contact plates projecting through said closed end on eitherside thereof internally and externally of said body portion, at leastone reversely arcuately folded switch blade in said housing formed fromthe same material and having one end thereof fixed to define a circuitconnection and the other end thereof provided with a multiple facecontact thereon and freely movable between spaced inner ends of a pairof contact plates for alternate electrical connection therewith, saidswitch blade being positioned for camming engagement of the free endthereof by said transverse plate during movement thereof toward saidclosed end to move said face contact out of engagement with one contactplate and into engagement with another, said movable free end of saidswitch blade forming a part of an inclined leg portion along which saidtransverse plate slides during switch actuation, and resilient meansurging said transverse plate away from said closed end to release saidswitch blade.

8. The switch assembly of claim 7 wherein said sealing ring is ofgenerally chevron-like configuration in cross section with a baseportion substantially filling said groove and a flexible lip portionangled from said groove into sealing engagement with said inner surfaceportions.

9. The switch assembly of claim 7 wherein a lamp unit is fixedly mountedin said body portion between said transverse plate and push-buttonmeans, the finger-like members of said push button means sliding freelythrough said lamp unit during movement of said transverse plate.

References Cited in the file of this patent UNITED STATES PATENTS

1. A SWITCH ASSEMBLY OF THE PUSH-BUTTON TYPE COMPRISING A HOLLOW BODYPORTION HAVING AN OPEN END AND A CLOSED END, A TRAVERSE PLATE IN SAIDBODY PORTION DIMENSIONED FOR SLIDING MOVEMENT LONGITUDINALLY THEREOF,PUSH ROD MEANS JOURNALED THROUGH THE CLOSED END OF SAID BODY PORTION FORRECIPROCAL MOVEMENT THERETHROUGH AND FIXED TO SAID PLATE, PUSH-BUTTONMEANS SLIDABLY RECEIVED IN THE OPEN END OF SAID BODY PORTION, SAIDPUSH-BUTTON MEANS BEING GENERALLY CUP-SHAPED WITH A CONTINUOUSTRANSVERSE END WALL PORTION JOINED WITH AN AXIAL PERPHERAL SKIRT PORTIONAND PROVIDED WITH RESILIENT FINGER-LIKE MEMBERS PROJECTING AXIALLYTHEREFROM ALONG INNER SURFACE PORTIONS OF SAID BODY PORTION INTORELEASABLE CONNECTION WITH EDGE PORTIONS OF SAID PLATE, THE END WALLPORTION OF SAID PUSH BUTTON MEANS PROJECTING FROM THE OPEN END OF SAIDBODY PORTION, SAID SKIRT PORTION INWARDLY OF SAID END WALL PORTION BEINGCIRCUMFERENTIALLY RECESSED TO DEFINE A GROVVE OPPOSED TO THE INNERSURFACE PORTIONS OF SAID BODY PORTION INWARDLY OF SAID OPEN END, ACONTINUOUS SEALING RING MOUNTED IN SAID GROOVE AND IN RESILIENT SLIDINGSEALING ENGAGEMENT WITH SAID INNER SURFACE PORTIONS, A PLURALITY OFELECTRICAL CONTACT PLATED PROPJECTING THROUGH SAID CLOSED END ON EITHERSIDE THEREOF INTERNALLY AND EXTERNALLY OF SAID BODY PORTION, AND ATLEAST ONE REVERSELY ARCUATELY FOLDED SWITCH BLADE IN SAID HOUSING FORMEDFROM RESILIENTLY MATERIAL AND HAVING ONE END THEREOF FIXED TO DEFINE ACIRCUIT CONNECTION AND THE OTHER END THEREOF PROVIDED WITH A MULTIPLEFACE CONTACT THEREON AND FREELY MOVABLE BETWEEN SPACED INNER ENDS OF APAIR OF CONTACT PLATES FOR ALTERNATE ELECTRICAL CONNECTION THEREWITH,SAID SWITCH BLADE BEING POSITIONED FOR CAMMING ENGAGEMENT OF THE FREEEND THEREOF BY SAID TRANSVERSE PLATE DURING MOVEMENT THEREOF TOWARD SAIDCLOSED END TO MOVE SAID FACE CONTACT OUT OF ENGAGEMENT WITH ONE CONTACTPLATE AND INTO ENGAGEMENT WITH ANOTHER.